Disposable, absorbent articles such as diapers, incontinence articles, sanitary towels, training pants and the like are well know in the art. Typically, disposable absorbent articles comprise a liquid pervious topsheet that faces the wearers body, a liquid impervious backsheet that faces the wearers clothing, and an absorbent core interposed between the liquid previous topsheet and the backsheet. The absorbent core must often be capable of absorbing and handling relatively large volumes of fluid like urine or other exudates discharged from the body of the wearer, and especially relatively large fluid volumes discharged over relatively short periods of time.
EP-A-0 774,242 discloses an absorbent article, having an uppermost (topsheet) material layer, which is directed towards the wearer's skin, and which is drained very effectively by an underlying acquisition/distribution region, such that a minimum of loosely bound liquid should remain in this layer in the topsheet.
It is also well known, to design articles, wherein the liquid barrier materials, often referred to as “backsheet” are gas or vapor permeable, thus allowing moisture to escape.
For applications, where the absorbency requirements are relatively minor, such as in so-called “panty-liner” products, non-woven or apertured polymeric film materials are often utilized as backsheets. For higher liquid loading, such as for baby diapers, microporous films, or so-called monolithic films are often preferred. Also known are various combinations fibrous layers with coating, films or the like.
Such breathable materials can be various kinds of webs, such as films which were rendered air/vapor permeable by aperturing as described in U.S. Pat. No. 5,628,737, or by exploiting the “microporosity” property as described in EP-A-0,238,200; EP-A-0,288,021; EP-A-0,352,802; EP-A-0,515,501; U.S. Pat. No. 4,713,068, whereby small voids are created within the film similar to very small cracks. WO 94/23107; WO 94/28224; U.S. Pat. No. 4,758,239; EP-A-0,315,013 all describe alternative breathable materials which can be fibrous textile or non-woven webs, with air/vapor easily penetrating through the relatively large pores of the structure. Such webs can be either untreated or treated with regard to improving their liquid impermeability properties, such as described in EP-A-0,196,654. In WO 95/16562 a laminate of a non-woven and a breathable film is disclosed. Further disclosures such as in WO 95/16746 relate to other materials allowing water molecules to diffuse through. Also, combinations of various materials comprising various layers any of the above elements are also well known.
The article should further be designed to retain not only the liquid discharged thereto, but also should provide a dry microclimate within the article, i.e. in the gas filled space between the article and the wearer.
PCT publication WO 98/58609 (Herrlein) discloses an article with a non-woven backsheet, wherein a dry micro climate is improved by using relatively high amounts of absorbent material, such as the so-called superabsorbent materials, when compared to the design capacity, i.e. the capacity to which the article is designed for the intended use.
A series of related and co-filed PCT applications (WO 00/10497; WO 00/10498, WO 00/104099, WO 00/10500, WO 00/10501) relates to breathable absorbent articles, including these being in the wet state. One approach described therein relates to creation of high permeability zones within an absorbent core, such as by aperturing the absorbent core, or by creating portions in the core containing substantially less high absorbency material than other portions of the core. Overall, the gas transfer mechanisms rely on gas diffusion mechanism, such as demonstrated by the preferred use of microporous film materials, as well as by the Tracer Gas Test.
However, there is still a need to provide absorbent articles with even further reduced tendency to create an undesirable high moisture content or relative humidity in the gas phase in the vicinity of the skin of the wearer, without compromising the liquid handling performance characteristics of the article, especially the acquisition and distribution properties.